A map distribution system that implements navigation using desired map data in which the degree of reliability of information about an object, such as a road or a facility, is taken into consideration is provided. A map distribution server 1a creates distribution data including difference map data and a reliance status showing the degree of reliability of the difference map data as a reply to edit request information about an edit request made by a user, and a map information terminal 3 receives the distribution data via a communication network 2 and performs navigation according to the reliance status included in the distribution data.

Claim:

The invention claimed is:

1. A map distribution server comprising: a receiving unit for receiving a distribution request including edit request information showing editorial contents of mapinformation requested by a user and a version of terminal map information held by a map information terminal; a first map information storage unit for holding a plurality of pieces of already-released first map information; a second map informationstorage unit for holding second map information which is most up to date, the second map information including yet-to-be-released map information; a first comparing unit for extracting first map information of a same version as said terminal mapinformation from among said plurality of pieces of first map information, and for making a comparison whether said edit request information is included in difference information between said extracted first map information and said second map informationto output a first comparison result showing a matching degree between the difference information and the edit request information; a creating unit for creating difference map data according to said distribution request on a basis of said firstcomparison result and said first map information of the same version; and a transmitting unit for transmitting distribution data which is said difference map data to said map information terminal.

2. The map distribution server according to claim 1, wherein the first comparing unit compares the difference information with the edit request information by calculating a matching degree showing a degree of match between them based on adifference between road shapes.

3. A map distribution server comprising: a receiving unit for receiving a distribution request including edit request information showing editorial contents of map information requested by a user and a version of terminal map information heldby a map information terminal; a first map information storage unit for holding a plurality of pieces of already-released first map information; a second map information storage unit for holding second map information which is most up to date, thesecond map information including yet-to-be-released map information; a first comparing unit for extracting first map information of a same version as said terminal map information from among said plurality of pieces of first map information, and formaking a comparison whether said edit request information is included in difference information between said extracted first map information and said second map information to output a first comparison result showing a matching degree between thedifference information and the edit request information; an extended map storage unit for holding extended map information comprised of photographic images corresponding to said first map information of the same version; a second comparing unit for,when the first comparison result indicates that the edit request information is not included in the difference information, making a comparison with the edit request information included in said distribution request by using said extracted first mapinformation and said extended map information to output a second comparison result; a creating unit for creating difference map data according to said distribution request on a basis of said second comparison result and said first map information of thesame version; and a transmitting unit for transmitting distribution data which is said difference map data to said map information terminal.

4. The map distribution server according to claim 3, wherein the first comparing unit compares the difference information with the edit request information by calculating a matching degree showing a degree of match between them based on adifference between road shapes.

5. The map distribution server according to claim 1 or 3, wherein the map information terminal is mounted in a vehicle, and the receiving unit receives the distribution request from another terminal which is placed outside said vehicle.

6. The map distribution server according to claim 5, wherein the other terminal placed outside the vehicle is a PC terminal.

7. The map distribution server according to claim 1 or 3, wherein said map distribution serve further includes an authentication unit for verifying registration of the map information terminal according to specific terminal ID information setto said map information terminal, and, when said authentication unit verifies that said map information terminal is a registered terminal, the map distribution server distributes the distribution data to said map information terminal, whereas when saidauthentication unit verifies that said map information terminal is not a registered terminal, said map distribution server sends a reply showing that said map distribution server cannot distribute the distribution data to said map information terminal.

8. The map distribution server according to claim 1 or 3, wherein said map distribution server further includes a point storage unit for storing distributable points to restrict a number of times that the map information terminal uses thedistribution request, and the map distribution server decrements said distributable points according to a number of times that said map information terminal has sent the distribution request, and, when said distributable points become equal to zero,disables the distribution to said map information terminal.

9. A map information terminal comprising: a terminal map information storage unit for storing terminal map information; a terminal handling unit for inputting edit request information showing editorial contents of said terminal mapinformation; a transmitting unit for transmitting the inputted edit request information to a distribution server; a receiving unit for receiving, as a reply to said edit request information transmitted to the distribution server, difference map datawhich are difference data corresponding to said terminal map information from the map distribution server; an updating unit for making a differential update of said terminal map information according to the difference map data included in saiddistribution data; and a navigation unit for carrying out a navigation function for performing map display.

10. The map information terminal according to claim 9, wherein the map information terminal further includes a point storage unit for storing distributable points to restrict a number of times that the map information terminal uses thedistribution request transmitted by the transmitting unit, and decrements said distributable points according to a number of times that said map information terminal has used said distribution request, and, when said distributable points are lost,transmission of the distribution request is disabled.

11. The map information terminal according to claim 10, wherein the map information terminal further includes a connecting terminal to which a storage medium for storing predetermined points is connected, and, when said storage medium isconnected to said connecting terminal, said predetermined points are added to the distributable points stored in the point storage unit.